2019-03-05 14:50:40

by Arnd Bergmann

[permalink] [raw]
Subject: [PATCH] [v2] xen: avoid link error on ARM

Building the privcmd code as a loadable module on ARM, we get
a link error due to the private cache management functions:

ERROR: "__sync_icache_dcache" [drivers/xen/xen-privcmd.ko] undefined!

Move the code into a new file that is always built in when Xen
is enabled, as suggested by Juergen Gross. Additional code will
be moved into this file later.

Signed-off-by: Arnd Bergmann <[email protected]>
---
v2: rename mm.o to xen-builtin.o, make it unconditional
---
drivers/xen/Makefile | 1 +
drivers/xen/privcmd.c | 30 +---------------------------
drivers/xen/xen-builtin.c | 41 +++++++++++++++++++++++++++++++++++++++
include/xen/xen-ops.h | 3 +++
4 files changed, 46 insertions(+), 29 deletions(-)
create mode 100644 drivers/xen/xen-builtin.c

diff --git a/drivers/xen/Makefile b/drivers/xen/Makefile
index ad3844d9f876..c3cbfcf30d38 100644
--- a/drivers/xen/Makefile
+++ b/drivers/xen/Makefile
@@ -2,6 +2,7 @@
obj-$(CONFIG_HOTPLUG_CPU) += cpu_hotplug.o
obj-y += grant-table.o features.o balloon.o manage.o preempt.o time.o
obj-y += mem-reservation.o
+obj-y += xen-builtin.o
obj-y += events/
obj-y += xenbus/

diff --git a/drivers/xen/privcmd.c b/drivers/xen/privcmd.c
index b24ddac1604b..290b6aca7e1d 100644
--- a/drivers/xen/privcmd.c
+++ b/drivers/xen/privcmd.c
@@ -723,26 +723,6 @@ static long privcmd_ioctl_restrict(struct file *file, void __user *udata)
return 0;
}

-struct remap_pfn {
- struct mm_struct *mm;
- struct page **pages;
- pgprot_t prot;
- unsigned long i;
-};
-
-static int remap_pfn_fn(pte_t *ptep, pgtable_t token, unsigned long addr,
- void *data)
-{
- struct remap_pfn *r = data;
- struct page *page = r->pages[r->i];
- pte_t pte = pte_mkspecial(pfn_pte(page_to_pfn(page), r->prot));
-
- set_pte_at(r->mm, addr, ptep, pte);
- r->i++;
-
- return 0;
-}
-
static long privcmd_ioctl_mmap_resource(struct file *file, void __user *udata)
{
struct privcmd_data *data = file->private_data;
@@ -809,15 +789,7 @@ static long privcmd_ioctl_mmap_resource(struct file *file, void __user *udata)
goto out;

if (xen_feature(XENFEAT_auto_translated_physmap)) {
- struct remap_pfn r = {
- .mm = vma->vm_mm,
- .pages = vma->vm_private_data,
- .prot = vma->vm_page_prot,
- };
-
- rc = apply_to_page_range(r.mm, kdata.addr,
- kdata.num << PAGE_SHIFT,
- remap_pfn_fn, &r);
+ rc = xen_remap_vma_range(vma, kdata.addr, kdata.num << PAGE_SHIFT);
} else {
unsigned int domid =
(xdata.flags & XENMEM_rsrc_acq_caller_owned) ?
diff --git a/drivers/xen/xen-builtin.c b/drivers/xen/xen-builtin.c
new file mode 100644
index 000000000000..8ad0d4900588
--- /dev/null
+++ b/drivers/xen/xen-builtin.c
@@ -0,0 +1,41 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Architecture independent helper functions for memory management
+ *
+ * Written by Paul Durrant <[email protected]>
+ */
+#include <linux/mm.h>
+#include <linux/export.h>
+
+struct remap_pfn {
+ struct mm_struct *mm;
+ struct page **pages;
+ pgprot_t prot;
+ unsigned long i;
+};
+
+static int remap_pfn_fn(pte_t *ptep, pgtable_t token, unsigned long addr,
+ void *data)
+{
+ struct remap_pfn *r = data;
+ struct page *page = r->pages[r->i];
+ pte_t pte = pte_mkspecial(pfn_pte(page_to_pfn(page), r->prot));
+
+ set_pte_at(r->mm, addr, ptep, pte);
+ r->i++;
+
+ return 0;
+}
+
+/* Used by the privcmd module, but has to be built-in on ARM */
+int xen_remap_vma_range(struct vm_area_struct *vma, unsigned long addr, unsigned long len)
+{
+ struct remap_pfn r = {
+ .mm = vma->vm_mm,
+ .pages = vma->vm_private_data,
+ .prot = vma->vm_page_prot,
+ };
+
+ return apply_to_page_range(vma->vm_mm, addr, len, remap_pfn_fn, &r);
+}
+EXPORT_SYMBOL_GPL(xen_remap_vma_range);
diff --git a/include/xen/xen-ops.h b/include/xen/xen-ops.h
index 4969817124a8..98b30c1613b2 100644
--- a/include/xen/xen-ops.h
+++ b/include/xen/xen-ops.h
@@ -109,6 +109,9 @@ static inline int xen_xlate_unmap_gfn_range(struct vm_area_struct *vma,
}
#endif

+int xen_remap_vma_range(struct vm_area_struct *vma, unsigned long addr,
+ unsigned long len);
+
/*
* xen_remap_domain_gfn_array() - map an array of foreign frames by gfn
* @vma: VMA to map the pages into
--
2.20.0



2019-03-05 14:12:56

by Boris Ostrovsky

[permalink] [raw]
Subject: Re: [PATCH] [v2] xen: avoid link error on ARM

On 3/5/19 8:30 AM, Arnd Bergmann wrote:
>
> diff --git a/drivers/xen/privcmd.c b/drivers/xen/privcmd.c
> index b24ddac1604b..290b6aca7e1d 100644
> --- a/drivers/xen/privcmd.c
> +++ b/drivers/xen/privcmd.c
> @@ -723,26 +723,6 @@ static long privcmd_ioctl_restrict(struct file *file, void __user *udata)
> return 0;
> }
>
> -struct remap_pfn {
> - struct mm_struct *mm;
> - struct page **pages;
> - pgprot_t prot;
> - unsigned long i;
> -};
> -
> -static int remap_pfn_fn(pte_t *ptep, pgtable_t token, unsigned long addr,
> - void *data)
> -{
> - struct remap_pfn *r = data;
> - struct page *page = r->pages[r->i];
> - pte_t pte = pte_mkspecial(pfn_pte(page_to_pfn(page), r->prot));
> -
> - set_pte_at(r->mm, addr, ptep, pte);
> - r->i++;
> -
> - return 0;
> -}
> -
> static long privcmd_ioctl_mmap_resource(struct file *file, void __user *udata)
> {
> struct privcmd_data *data = file->private_data;
> @@ -809,15 +789,7 @@ static long privcmd_ioctl_mmap_resource(struct file *file, void __user *udata)
> goto out;
>
> if (xen_feature(XENFEAT_auto_translated_physmap)) {
> - struct remap_pfn r = {
> - .mm = vma->vm_mm,
> - .pages = vma->vm_private_data,
> - .prot = vma->vm_page_prot,
> - };
> -
> - rc = apply_to_page_range(r.mm, kdata.addr,
> - kdata.num << PAGE_SHIFT,
> - remap_pfn_fn, &r);
> + rc = xen_remap_vma_range(vma, kdata.addr, kdata.num << PAGE_SHIFT);

I wonder whether drivers/xen/xlate_mmu.c might be a good place for these
routines.

-boris

2019-03-05 14:49:48

by Jürgen Groß

[permalink] [raw]
Subject: Re: [PATCH] [v2] xen: avoid link error on ARM

On 05/03/2019 14:30, Arnd Bergmann wrote:
> Building the privcmd code as a loadable module on ARM, we get
> a link error due to the private cache management functions:
>
> ERROR: "__sync_icache_dcache" [drivers/xen/xen-privcmd.ko] undefined!
>
> Move the code into a new file that is always built in when Xen
> is enabled, as suggested by Juergen Gross. Additional code will
> be moved into this file later.
>
> Signed-off-by: Arnd Bergmann <[email protected]>
> ---
> v2: rename mm.o to xen-builtin.o, make it unconditional
> ---
> drivers/xen/Makefile | 1 +
> drivers/xen/privcmd.c | 30 +---------------------------
> drivers/xen/xen-builtin.c | 41 +++++++++++++++++++++++++++++++++++++++
> include/xen/xen-ops.h | 3 +++
> 4 files changed, 46 insertions(+), 29 deletions(-)
> create mode 100644 drivers/xen/xen-builtin.c
>
> diff --git a/drivers/xen/Makefile b/drivers/xen/Makefile
> index ad3844d9f876..c3cbfcf30d38 100644
> --- a/drivers/xen/Makefile
> +++ b/drivers/xen/Makefile
> @@ -2,6 +2,7 @@
> obj-$(CONFIG_HOTPLUG_CPU) += cpu_hotplug.o
> obj-y += grant-table.o features.o balloon.o manage.o preempt.o time.o
> obj-y += mem-reservation.o
> +obj-y += xen-builtin.o
> obj-y += events/
> obj-y += xenbus/
>
> diff --git a/drivers/xen/privcmd.c b/drivers/xen/privcmd.c
> index b24ddac1604b..290b6aca7e1d 100644
> --- a/drivers/xen/privcmd.c
> +++ b/drivers/xen/privcmd.c
> @@ -723,26 +723,6 @@ static long privcmd_ioctl_restrict(struct file *file, void __user *udata)
> return 0;
> }
>
> -struct remap_pfn {
> - struct mm_struct *mm;
> - struct page **pages;
> - pgprot_t prot;
> - unsigned long i;
> -};
> -
> -static int remap_pfn_fn(pte_t *ptep, pgtable_t token, unsigned long addr,
> - void *data)
> -{
> - struct remap_pfn *r = data;
> - struct page *page = r->pages[r->i];
> - pte_t pte = pte_mkspecial(pfn_pte(page_to_pfn(page), r->prot));
> -
> - set_pte_at(r->mm, addr, ptep, pte);
> - r->i++;
> -
> - return 0;
> -}
> -
> static long privcmd_ioctl_mmap_resource(struct file *file, void __user *udata)
> {
> struct privcmd_data *data = file->private_data;
> @@ -809,15 +789,7 @@ static long privcmd_ioctl_mmap_resource(struct file *file, void __user *udata)
> goto out;
>
> if (xen_feature(XENFEAT_auto_translated_physmap)) {
> - struct remap_pfn r = {
> - .mm = vma->vm_mm,
> - .pages = vma->vm_private_data,
> - .prot = vma->vm_page_prot,
> - };
> -
> - rc = apply_to_page_range(r.mm, kdata.addr,
> - kdata.num << PAGE_SHIFT,
> - remap_pfn_fn, &r);
> + rc = xen_remap_vma_range(vma, kdata.addr, kdata.num << PAGE_SHIFT);
> } else {
> unsigned int domid =
> (xdata.flags & XENMEM_rsrc_acq_caller_owned) ?
> diff --git a/drivers/xen/xen-builtin.c b/drivers/xen/xen-builtin.c
> new file mode 100644
> index 000000000000..8ad0d4900588
> --- /dev/null
> +++ b/drivers/xen/xen-builtin.c
> @@ -0,0 +1,41 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Architecture independent helper functions for memory management
> + *
> + * Written by Paul Durrant <[email protected]>
> + */
> +#include <linux/mm.h>
> +#include <linux/export.h>

Shouldn't you #include xen/xen-ops.h here as well?


Juergen

2019-03-05 15:53:24

by Jürgen Groß

[permalink] [raw]
Subject: Re: [PATCH] [v2] xen: avoid link error on ARM

On 05/03/2019 14:43, Boris Ostrovsky wrote:
> On 3/5/19 8:30 AM, Arnd Bergmann wrote:
>>
>> diff --git a/drivers/xen/privcmd.c b/drivers/xen/privcmd.c
>> index b24ddac1604b..290b6aca7e1d 100644
>> --- a/drivers/xen/privcmd.c
>> +++ b/drivers/xen/privcmd.c
>> @@ -723,26 +723,6 @@ static long privcmd_ioctl_restrict(struct file *file, void __user *udata)
>> return 0;
>> }
>>
>> -struct remap_pfn {
>> - struct mm_struct *mm;
>> - struct page **pages;
>> - pgprot_t prot;
>> - unsigned long i;
>> -};
>> -
>> -static int remap_pfn_fn(pte_t *ptep, pgtable_t token, unsigned long addr,
>> - void *data)
>> -{
>> - struct remap_pfn *r = data;
>> - struct page *page = r->pages[r->i];
>> - pte_t pte = pte_mkspecial(pfn_pte(page_to_pfn(page), r->prot));
>> -
>> - set_pte_at(r->mm, addr, ptep, pte);
>> - r->i++;
>> -
>> - return 0;
>> -}
>> -
>> static long privcmd_ioctl_mmap_resource(struct file *file, void __user *udata)
>> {
>> struct privcmd_data *data = file->private_data;
>> @@ -809,15 +789,7 @@ static long privcmd_ioctl_mmap_resource(struct file *file, void __user *udata)
>> goto out;
>>
>> if (xen_feature(XENFEAT_auto_translated_physmap)) {
>> - struct remap_pfn r = {
>> - .mm = vma->vm_mm,
>> - .pages = vma->vm_private_data,
>> - .prot = vma->vm_page_prot,
>> - };
>> -
>> - rc = apply_to_page_range(r.mm, kdata.addr,
>> - kdata.num << PAGE_SHIFT,
>> - remap_pfn_fn, &r);
>> + rc = xen_remap_vma_range(vma, kdata.addr, kdata.num << PAGE_SHIFT);
>
> I wonder whether drivers/xen/xlate_mmu.c might be a good place for these
> routines.

Hmm, probably. This would require a stub in the header to avoid
problems in case of CONFIG_XEN_AUTO_XLATE not defined, though
(the #ifdef is already there).

I think this is the cleanest solution.


Juergen

2019-03-05 17:40:58

by Arnd Bergmann

[permalink] [raw]
Subject: Re: [PATCH] [v2] xen: avoid link error on ARM

On Tue, Mar 5, 2019 at 3:57 PM Juergen Gross <[email protected]> wrote:
> On 05/03/2019 14:43, Boris Ostrovsky wrote:
> > On 3/5/19 8:30 AM, Arnd Bergmann wrote:

> >> @@ -809,15 +789,7 @@ static long privcmd_ioctl_mmap_resource(struct file *file, void __user *udata)
> >> goto out;
> >>
> >> if (xen_feature(XENFEAT_auto_translated_physmap)) {
> >> - struct remap_pfn r = {
> >> - .mm = vma->vm_mm,
> >> - .pages = vma->vm_private_data,
> >> - .prot = vma->vm_page_prot,
> >> - };
> >> -
> >> - rc = apply_to_page_range(r.mm, kdata.addr,
> >> - kdata.num << PAGE_SHIFT,
> >> - remap_pfn_fn, &r);
> >> + rc = xen_remap_vma_range(vma, kdata.addr, kdata.num << PAGE_SHIFT);
> >
> > I wonder whether drivers/xen/xlate_mmu.c might be a good place for these
> > routines.
>
> Hmm, probably. This would require a stub in the header to avoid
> problems in case of CONFIG_XEN_AUTO_XLATE not defined, though
> (the #ifdef is already there).
>
> I think this is the cleanest solution.

Putting it into xlate_mmu.c was my first attempt, but I was not sure how to
solve the dependency on CONFIG_XEN_AUTO_XLATE. So
xen_feature(XENFEAT_auto_translated_physmap)) would be guaranteed
to return false if CONFIG_XEN_AUTO_XLATE is disabled?

Arnd

2019-03-05 17:41:10

by Jürgen Groß

[permalink] [raw]
Subject: Re: [PATCH] [v2] xen: avoid link error on ARM

On 05/03/2019 17:49, Arnd Bergmann wrote:
> On Tue, Mar 5, 2019 at 3:57 PM Juergen Gross <[email protected]> wrote:
>> On 05/03/2019 14:43, Boris Ostrovsky wrote:
>>> On 3/5/19 8:30 AM, Arnd Bergmann wrote:
>
>>>> @@ -809,15 +789,7 @@ static long privcmd_ioctl_mmap_resource(struct file *file, void __user *udata)
>>>> goto out;
>>>>
>>>> if (xen_feature(XENFEAT_auto_translated_physmap)) {
>>>> - struct remap_pfn r = {
>>>> - .mm = vma->vm_mm,
>>>> - .pages = vma->vm_private_data,
>>>> - .prot = vma->vm_page_prot,
>>>> - };
>>>> -
>>>> - rc = apply_to_page_range(r.mm, kdata.addr,
>>>> - kdata.num << PAGE_SHIFT,
>>>> - remap_pfn_fn, &r);
>>>> + rc = xen_remap_vma_range(vma, kdata.addr, kdata.num << PAGE_SHIFT);
>>>
>>> I wonder whether drivers/xen/xlate_mmu.c might be a good place for these
>>> routines.
>>
>> Hmm, probably. This would require a stub in the header to avoid
>> problems in case of CONFIG_XEN_AUTO_XLATE not defined, though
>> (the #ifdef is already there).
>>
>> I think this is the cleanest solution.
>
> Putting it into xlate_mmu.c was my first attempt, but I was not sure how to
> solve the dependency on CONFIG_XEN_AUTO_XLATE. So
> xen_feature(XENFEAT_auto_translated_physmap)) would be guaranteed
> to return false if CONFIG_XEN_AUTO_XLATE is disabled?

Yes.


Juergen